Our work examines the molecular basis of plant disease resistance. Plant immune systems include many elements that are unique to plants. We study disease resistance in part because host-pathogen dynamics and the molecular workings of immune systems are fascinating biological topics. On a more practical level, one of the best ways to control plant diseases is by genetically determined resistance. Genetic resistance is convenient for growers and minimizes the need for costly, time-consuming and/or potentially toxic external treatments. Plant breeders and their predecessors have selected for improved plant disease resistance since the dawn of agriculture, but the molecular basis of this resistance is only partly understood. We work to identify and study the genes and the biochemical/cellular processes that control pathogen recognition, defense signal transduction, and the execution of successful resistance responses. We seek to expand our basic understanding of plant interacations with pathogens, anticipating that some of this work will contribute to the development of plants with improved disease resistance. Our research has often utilized Arabidopsis thaliana because of the extraordinary experimental versatility of this plant species. We have often studied responses to the bacterial blight pathogen Pseudomonas syringae pv tomato. Most of our work is now focused on soybean, the most abundant legume crop and a major contributor to world food supplies. In particular, we are discovering mechanisms of soybean resistance to the important soybean pathogen soybean cyst nematode (Heterodera glycines).